Pressure sensitive record material



Patented pro 25, 1950 so s'rArEs sans rim

PRESSURE SENSITIVE RECORD MATERIAL Barrett Green. Dayton. (thin, assignor to The National lash Register Company, Dayton, Ohio, a corporation of Maryland i 12 Claims. (ciQna-ss) This invention relates to improvements .in pressure-sensitive record material. This application is a division of the pending application of Bar rett K. Green, Serial No. 584,938, filed November 8, 194.7, for Pressure-sensitive record material.

The principalobject-of this invention is to provide a pressure-sensitive record material on which a-mark of distinctive color may be produced by the mere application of localized pressure and which is not subject .to the disadvantages inherent in the pressure-sensitive record material disclosed in- United States Letters Patent No. 2,299,693, patented-October 20, 1942, on the ape plication filed by Barrett K. Green on February 23, 1940. That patent discloses a, pressure-sensitive record material including the combination of an insulating medium, arupturable solid material such as gum dammar, having included therein interspersed droplets of a plurality of liquid reagents, which are chemically reactive to produce a distinctive color in the record ma-- terial at the points of application of localized pressure thereto, such pressure rupturing the insulating medium to permitchemical reaction between the two liquid reagents. The two reagents disclosed in this patent are gallic acid and ferric ammonium sulphate, each i dissolved in glycerine, These reagents are ionized by the glycerine, which constitutes an ionizing medium, and. theehemical reaction proceeds byinterchange of ions when the two solutions are allowed to mix, upon the ru ture of the insulatin medium. The reaction disclosed in that patent depends upon the presenceof th reagents in an ionizing medium. Hos-ever, any available ionizing medium is hygroscopic. with the result rhatthe record mate.- rial made in accordance with this patent is sensitive to an excessofmois-uraand conditions of h gh hum dity may cause the insulating medium to cease to beeffective. wi h the result that the chemical reaction "takes place without any application of localized pressure, and the record material is stainedand discolored,,so=that it ceases tobe useful.

- As stated above, the principal object of the present invention .is to provide .a pressure-sensitive :record material that is not subject to the defects and disadvantages of that disclosed in Patent No. 2,299,693, as indicated. above.

Another object of the present invention is to provide a record material upon which a mark of distinctive color may be produced. at the points i of application .oflocalized pressure there to, by such mere application .of localized pressure. and which will not become discolored or 2 stained due to the efiect of light, atmospheric conditions, or aging.

.In shortit is the object of this invention to provide a pressure-sensitive record material .in which the mark of distinctive color will be producedonlyat the points of application of localized pressure, and at no other points, and under no other conditions.

Another object of this invention is to provide l a pressure-sensitive recordmaterial in which the mark .ofdistinctive color is produced by the chemical reaction of color-forming reactants, in the absence of any liquid ionizing medium therefor. i

A iurther object of this invention is to providea pressure-sensitive record material in which amark of distinctive color is produced by a reaction between solid particles of color-forming reactants.

Further objects, and objects relating to details and economies of production, will definitely appear from the detailed description to follow. The obiects of this invention have been attained by the several embodiments thereof described in detail in the following specification. This invention is clearlydefined and pcinted'out in the appended claims.

.In :general, the present invention contemplates apressure-sensitive record material comprising, in combination, a plurality of adsorption color-forming reactants, such reactants being so selected that they react, in the absence of a liquid ionising medium for the reactants, to form a distinctive'color when brought into adsorption contact with each other, and a solid insulating medium insulating said reactants from color,- iorming reaction contact with each other. Upon application of localized pressure to the record material, as by drawins a stylus across it, the insulating medium is ruptured at the points of application of said local zed pressure. and such rupture permits color-forming reaction contact between the reactants at such points, in the absence of any liquid ionizing medium for said reactants. The result is that a mark of distinctive color is produced by the mere application of localized pressure;

The color-forming reaction employed is of the, so-called, adsorption type'in which an inorganic material causes a color change in an organic material in adsorption contact therewith.

Oi the reactantmaterials employed theorganic material; an electron donor aromatic com- .pound havingadouble bond system which isconvertible ltofla more highly polarized conju ated form upon taking part in an electron acceptordonor solid surface chemical reaction, giving it a distinctive color, and the inorganic material is a material which is an acid relative to the organic material so as to be an electron acceptor when in adsorption contact therewith. Both materials are in fine particle form in order to furnish a large reactant surface area per unit area of the record material which enhances the depth of color per unit area of the record material.

In the preferred form of this invention, both of the color-forming reactants, as well as the insulating medium, are in the solid state, and the color-forming reaction takes place upon mere contact of solid particles of the reactants. A pressure-sensitive record material may be provided in which the solid particles of a plurality of color-forming reactants are dispersed in a solid insulatin medium, which insulates the particles from color-forming reaction contact with each other. The rupture of this solid insulating medium by the application of localized pressure permits the solid particles of color-forming reactants to react with each other, at the points of application of such pressure, to produce the mark of distinctive color. According to one form of this invention, solid particles of one of the colorforming reactants are carried by and dispersed in a solid insulating medium, to which a coating of solid particles of another color-form ng reactant is applied. In this case, the application of localized pressure ruptures the solid insulating medium at the points of application of such pressure and brings about, color-forming reaction contact between the solid particles of color-forming reactants at such points, thus producing the mark of distinctive color. Preferably, this pressure-sensitive record material includes a base web, such as a fibrous web of paper or the like, to which the coating of solid insulating medium and the color-forming reactants is applied.

Since it is diflicult to show precisely the spatial relationship between the solid particles of colorforming reactants, the solid insulating medium,

and the base web, it is preferred not to attempt to illustrate any embodiment of this invention by drawings.

In the following examples, there will be described embodiments of this invention, by means of which the objects of the invention have been successfully attained.

One embodiment of this invention is pressuresensitive record material consisting of a web of paper having applied thereto a coating including casein as the solid insulating medium and solid particles of two color-forming reactants; namely, kaolin and the compound 2(4,4' bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid, having the structural formula In this embodiment the casein constitutes the solid insulating medium, insulating the solid particles of kaolin and the compound 201,4 bis dimethylaminobenzohydryl) 5 dimethylaminoben 4 zoic acid from color-forming reaction contact with each other. The record material is normal- 1y white, and the application of localized pressure thereto ruptures the solid insulating medium at the points of application of such pressure,

permitting color-forming reaction contact between the solid particles of the reactants, producing a dark blue mark.

The compound 201,4 bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid, referred to above, is described and claimed in the pending application of C yde S. Adams, Serial No. 599,968, filed June 16, 1945, now Patent No. 2,458,328, for 201.4 bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid.

This record material has been successfully produced by first coating a web of paper with a casein solution having solid particles of kaolin dispersed therein, the ratio of kaolin to casein being about ten to one. This coating having been dried, the coated side of the paper was treated with a 3% by weight solution of the compound 2(4A' bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid in ethyl alcohol. The excess of solution was removed, and the treated paper was then dried to evaporate the solvent.

When these ingredients are applied to the paper as a coating thereon, such coating should weigh about .0023 pound per square foot of surface and may have a thickness of the order of from .0905 to .001 inch. The thickness of the coating varies, of course, with the treatment to which the record material is subjected in finishing. The solid particles of kaolin in this record material may be of about the order of ten microns in diameter, although considerable variation in particle size is possible without any ill effects.

Particle size of the benzoic acid compound is determined by the method of application of that ingredient. The particles of these reactants may be as large as ten microns in diameter and frequently are much smaller.

Organic hydrophilic film-forming colloid substances such as gelatin, methyl cellulose, starch, polyvinyl alcohol, and animal glue are representative materials that may be substituted for casein as the solid insulating medium. Any of the following inorganic materials may be substituted for kaolin as one of the color-forming reactants: attap lgite (Attapulgus clay), talc, bentonite, halloysite, and magnesium trisilicate. When any of these materials are substituted for the kaolin in this combination, the resulting record material will be white or bluish white in color, and a dark blue mark will a pear thereon as the result of the application of localized pressure.

One method that has been used successfully to make the pressure-sensitive record material described above is as follows: A slurry of kaolin and water was prepared including fifty parts by weight of kaolin to fifty parts by weight of water, and a small amount of a suitable dispersing agent, such a sodium metaphosphate, for instance, in the proportion of 0.075% by weight was added to facilitate the dispersion of the particles of kaolin throughout the slurry. The addition of this dispersing a ent reduces the viscosity of the slurry considerably, thus facilitating its mixing and application and also preventing the settling of the solid particles of kaolin. A 20% by weight solution of casein in water was formed by, first, dispersin; the casein in cold water by stirring for fifteen minutes at room temperature and, then,-heating up to degrees Centigrade;

Five parts by weight of a 28% ammonium hydroxide so1ution-that" is, one having a specific gravity of25.'9 31%;, at

were then added to the hotcasein solution, which was stirred for about fifteen minutes and al lowed to cool to room temperature. The kaolin slurryland the alkaline casein-solution were then thoroughly mixedandblendedin the ratio of ten parts by Weight of kaolin to one part! casein, and, at this stage, a small percentage-for instance, about 0.05% by weight-of tributyl phosphate in alcohol, or other anti-foaming agent, was added. This mixture of the kaolin slurry and the caseinsolution was then applied as a coating to the paper, and the coated paper was dried and calendered, or treated in any desired way to give proper surface finish, A solution in ethyl alcohol of about 3% by weight of the benzoic acid compound was then applied to the coated side of the paper, the excess, of this solution was removed in any suitable way, .as by passing under a doctor blade, and then the treated paper was dried to evaporate :the. toluene and was ready for use.

Themethodsand processes of making pressuresensitive record material disclosed herein are not claimed inthis application but are disclosed and claimed in the pending applicationot Barrett K. Green, Serial No. 78%,939, filed November 8,, 1947, for Process for making pressure-sensitive record material, and in the division thereof, Serial No. 63,217, filed DccembcrrZ, 61948.

It is understood that the pressureasensitive record material describedherein is susceptible of considerable variation without departing from the spirit of the invention.

What is claimed is:

1. Pressure-sensitive record materialincluding the combination of asupporting member, a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of a liquid ionizing medium for the reactants to form a distinctive color when brought into adsorption contact with each other, at least one of said reactants being an inorganic compound and at least another of said reactants being an organic compound, disposed in proximity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid material, insulating said reactants from color-forming reaction contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-forming reactants being the organic compound 201,4 bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid, having the structure nen),

the inorganic reactant being in fineparticle dorm toprov-ide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound, and the organic compound and inorganic material being adsorba-ble one upon theother.

2. The record material of claim 1in-which the inorganic color-forming reactant is kaolin.

3. The record material ofclaim 2 in which the solid insulating medium is casein.

4. Pressure-sensitive record material including the combination of a supporting member, solid particles of a plurality of adsorption colorforming reactants disposed in contiguity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid material, insulating said solid reactant particles from color-forming reaction contact with each other, at least one of the reactants being an inorganic compound-and at leastanother orient the reactants -being an organic compound adsorbable one \upon the other, said reactants'being, so selectedas to reacttoform a distinctive color when particles of each are brought into adsorption contact, the application of localized pressure to the, record material rupturing said insulatingmedium atthe. points of application of :such pressure to permit color-formingreaction contact-of the solid reactant particles atsuch points-whereby amark of distinctive color is produced by mere application of localized pressure, one of said" color-forming reactants being the organic compound 201,4 bis dimethylaminobenzohydryl) 5 dimethylaminobenzoic acid, having the strucand the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

5. The record material of claim 4 in which the inorganic color-forming reactant is kaolin.

6. The record material of claim 5 in which the solid insulating medium is casein.

7. Pressure-sensitive record material including the combination of a supporting member, a solid insulating medium derived from an organic film-forming hydrophilic colloid substance, solid particles of a first color-forming reactant dispersed therein and solid particles of a second color-forming reactant deposited thereon, said solid insulating medium insulating said solid reactant particles from color-forming reaction contact with each other, one of said reactants being an inorganic compound and the other reactant being an organic compound, one adsorbable on the other, said reactants being so selected as to react, in the solid state, to form a distinctive color when brought into adsorption contact with each other, the application of local; ized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, said second color-forming reactant being the organic compound 2(4,4 bis dimethylaminobenzohydryl) 5-dimethylaminobenzoic acid, having the structure and the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

8. The record material of claim '7 in which the first color-forming reactant is kaolin.

9. The record material of claim 8 in which the solid insulating medium is casein.

10. Pressure-sensitive record material including the combination of a base web and a coating thereon, said coating including a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of an ionizing medium to form a distinctive color when brought into contact with each other, at least one of said reactants being an inorganic compound and at least another one of the reactants being an organic compound adsorbable therewith, and disposed in proximity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid COIH and the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound. 11.' The record material of claim 10 in which the inorganic color-forming reactant is kaolin. 12. The record material of claim 11 in which the solid insulating medium is casein.

BARRETT K. GREEN.

REFERENCES 'C'ITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain .l Jan. 4, 1943 Number 

1. PRESSURE-SENSITIVE RECORD MATERIAL INCLUDING THE COMBINATION OF A SUPPORTING MEMBER, A PLURALITY OF ADSORPTION COLOR-FORMING REACTANTS IN THE SOLID STATE, SO SELECTED AS TO REACT IN THE ABSENCE OF A LIQUID IONIZING MEDIUM FOR THE REACTANTS TO FORM DISTINCTIVE COLOR WHEN BROUGHT INTO ADSORPTION CONTACT WITH EACH OTHER, AT LEAST ONE OF SAID REACTANTS BEING AN INORGANIC COMPOUND AND AT LEAST ANOTHER OF SAID REACTANTS BEING AN ORGANIC COMPOUND, DISPOSED IN PROXIMITY TO EACH OTHER, AND A SOLID INSULATING MEDIUM, DERIVED FROM AN ORGANIC FILM-FORMING HYDROPHILIC COLLOID MATERIAL, INSULATING SAID REACTANTS FROM COLOR-FORMING REACTION CONTACT WITH EACH OTHER, THE APPLIATION OF LOCALIZED PRESSURE TO THE RECORD MATERIAL RUPTURING SAID INSULATING MEDIUM AT THE POINTS OF APPLICATION OF SUCH PRESSURE TO PERMIT COLOR-FORMING REACTION CONTACT BETWEEN THE REACTANTS AT SUCH POINTS, WHEREBY A MARK OF DISTINCITIVE COLOR IS PRODUCED BY MERE APPLICATION OF LOCALIZED PRESSURE, ONE OF THE COLOR-FORMING REACTANTS BEING THE ORGANIC COMPOUND 2(4,4'' BIS DIMETHYLAMINOBENZOHYDRYL) 5 DIMETHYLAMINOBENZOIC ACID, HAVING THE STRUCTURE. 